The present invention relates to a transmission device for automotive vehicles with traction control and cruise control. The transmission device is interposed into the path of force transmission from a drive control pedal, such as an accelerator pedal or a corresponding control lever, to a control member of the vehicle driving engine. The control member can be the throttle-flap of an internal-combustion engine, or the adjusting lever of the injection pump of a spark-ignition engine, or the like. A traction control unit engages the transmission device.
Traction control systems are known which, in the presence of excessive traction slip, intervene into the path of force transmission from the accelerator pedal to the control member of the driving engine. That is, the throttle-flap or the injection pump adjusting lever, and which reduce the drive power of the engine. As soon as the coefficient of adherence between tire and road is sufficient again, the drive power is increased again by virtue of this control. German published patent application Nos. 30 21 116 and 33 37 664 describe such systems, wherein the auxiliary energy which resets the throttle-flap or the adjusting lever in opposition to the actuating force exerted on the accelerator pedal is generated in the form of hydraulic energy. It is likewise known to use electric motors for the generation of the resetting torques. The provision of control devices for maintaining the preselected speed of an automotive vehicle constant is also known. To this end, electric servo motors can be used for instance which, instead of the accelerator pedal, adjust the throttle-flap or the injection pump of the driving engine.
It is advisable to equip vehicles with systems for traction control and systems for cruise control which are independent of one another. This necessitates substantial expenditure. As both systems may generate contradicting commands, provisions must be made to prevent interferences caused thereby such as permanent switch-over and the like.
It is an object of the present invention to develop a device which is structurally simple and can be manufactured with comparatively little effort, and which lends itself to being used for traction control as well as for cruise control. A disengagement of both types of control is ensured in order to avoid the above-mentioned shortcomings.